The Democratic race may be decided by superdelegates. They should follow the voters, not defy them

James Madison, the architect of the constitution, always maintained that America was not a democracy but a republic. A democracy was government by the people (something many of the founders considered akin to mob rule), while a republic, Madison wrote in "Federalist No. 10," is "a government in which the scheme of representation takes place."

This scheme of representation is where it gets tricky. The inherent tension in a representative democracy is, Should our elected leaders vote according to their judgmentor their constituency? Political theorists have debated this for two centuries. These days, you generally hear...